These studies are directed toward the characterization of human lymphoid neoplasms, particularly those of the B-cell type. We hope to develop a better definition of a clinically applicable taxonomy and to exploit the biological "tumor" markers in an attempt to detect the minimal disease. We will explore aspects of pathogenesis and alternative therapeutic approaches in these tumors. Antibody-secreting cells making antitumor antibodies (anti-idiotypic antibodies) are being cloned, and individual clones are being sought to develop a library of antisera to be used in the detection of different forms of B-cell tumors in humans. Exploiting the fluorescence-\ activated cell sorter, an "immunological fingerprint" of each tumor is now being carried out, and a search for clinical correlates with the specific fingerprints is in progress. The secreted products of these tumors and the responsiveness of tumors to mitogens and T-cell signals are also being used for classification and in an attempt to apply these for the diagnosis of minimal disease. These studies propose a phenotypic characterization of the immunological form of human lymphoid neoplasms that can be correlated with the classical histological characterization of these tumors and provide criteria for therapeutic intervention.